Perl 5.6 fixes (ITS#1659)

Full_Name: Luke Howard
Version: 2.1.0alpha
OS: Linux
URL: http://www.padl.com/~lukeh/2.1.0alpha+perlfixes.diff
Submission from: (NULL) (203.2.135.22)
A small change was needed to compile 2.1.0alpha with Perl 5.6.x
as opposed to Perl 5.005. Moreover, we made some changes to improve
the interface between the back-perl glue and the actual Perl backend:
it is, for example, useful for the search implementation to be
aware of the search scope and normalized base DN, and for backend
methods to return actual LDAP result codes rather than TRUE/FALSE.
Caveat utilitor being that we haven't finished testing these patches;
review advised.